Muffler.



PATENTED DEC. 3, 1907.

D. REID.

MUFFLER.

APPLIOATION FILED JULY 22, 1904. RENEWED JUNE 19, 1905.

aka/nu,

- Muflier, of which the following is UNITED STATES PATENT OFFICE.

DAVID REID, OF ITHAGA, NEW YORK.

MUFFLER.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed July 22. 1904. Serial No. 217.68%. Renewed June 19.1905. Serial No. 266.044.

To all whom it may concern:

Be it known that 1, DAVID REID, a subject of the King of Great Britain,residing at Ith aca, in the county of Tompkins and State of New York,have invented a new and useful a specification.

My invention relates to muffling devices such as are used to silence theexhaust of heat engines. v

Heretofore two general methods of muffling the exhaust from heat engineshave been used. In one method the surplus heat is abstracted from theexhaust fluid by bringing it in contact with a cooling medium before ithas an opportunity to expand freely. For successful operation of such asystem there must be a comparatively large body of the cooling medium,or some effective means for keeping the medium at a sufficiently lowtemperature, and both of these necessary features are objectionable,especially in the case of portable motors. 1n the second method ofmuifling referred to, means are provided to cause the gradual expansionof the exhaust fluid, thus preventing the concussion and noise thatattends free expansion in the open air. This gradual expansion has beenattended in all cases, so far as I am aware, with a considerable backpressure that materially reduces the power of the engine.

The object of the present invention is the production of a muflier thateffectively uses the atmosphere as a cooling medium, that causes agradual expansion of the exhaust fluids without the production of anyeffective back ressure, that is of simple construction and t at islight, strong and compact.

To this end the invention consists in certain combinations and featuresof construction which are fully set forth in the following descriptionin connection with the accomanying drawings which illustrate thepreerred form of my invention.

In the following description and appended claims I shall use the termgas in referring to the exhaust fluid for the sake of convenience andfor the further reason that my muffler is especially adapted for use inconnection with internal combustion motors. At the same time I wouldhave. it understood that I do not intend by so doing to restrict thescope of my invention.

Referring to the drawings, Figure 1 is a central, longitudinal sectionthrough the body of the mufller which is cylindrical in form; Fig. 2 isa detached view of two of the baffling cones showing certain details ofconstruction; Fig. 3 is an end view, and Fig. 4 a sectional view of amodified form of nozzle. The muffler as illustrated is cylindrical inform, the side wall 1 being preferably formed of two thicknesses ofsheet metal spaced apart so as to form an annular chamber adapted toreceive asbestos fiber or any other suitable non-conductor. The ends ofthe muflier are closed by heads 2 and 3. The head 2 opens centrallythrough a hollow boss 4 to receive the exhaust pipe from the engine,while a similar boss 5 on the head 3 forms the outlet of the muffler.The boss 5 may open directly to the atmosphere or re ceive a pipe thatopens to the atmosphere at a distance from the mufller. Rings 6 and 7are formed integral with the heads 2 and 3, respectively, the ringsbeing borne by radial ribs that project from the inner faces of theheads. These rings receive a tube 8 and upon this axial tube arearranged a series of sheet metal baffling cones 9. Each cone is formedwith a series of perforations and these perforations occur alternatelyat the inner and outer edges of the cones, as shown in Fig. 1, also inFig. 2 where a portion of the nearer cone is broken away to show theperforations of the one back of it. Further more, in the preferred formof my muffler, the perforations progressively increase in capacity fromthe inlet to the outlet end of the muffler, and at no place is thecapacity of the muffler passages less than that of the engine exhaustpipe which the muffler is adapted to receive.

The baffling cones are spaced by means of sheet metal ribs 10 which,after being bent to form, are secured to the cones by riveting as shownin Fig. 2. While I prefer this method of spacing the cones other meanscan be employed for example, the cones may be made alternately plane andcorrugated. The use of conical baffle plates in a cylindrical casingforms chambers 11 and 12 at the ends of the muffler. These chambers areof considerable volume and, especially in the case of chamber 11,perform an important function in the operation of the muffler. Inaddition to the cones, plane perforated baffle plates 13 {and 14 areinterposed between the cones and the two heads of the muffler.

. the conical baffle plates.

lar passage 16 that communicates with the chamber 11. The inlet end ofthe tube is provided with a nut 17 and, as the nozzle also acts as anut, the tube is adapted'tov serve as'a tie rod and binds the parts ofthe structure securely together. I prefer, however, to supplement thismeans of securing the parts by providing a series of tie rods 18 thatpass between the inner and outer members of the wall 1. The holes thatare drilled in the heads 2 and3 to receive these rods, are so disposedthat when the rods are placed under tension they are drawn against theinner member of the wall 1 and aid materially in strengthening thestructure so that a mufiler explosion is sustained without injury.

In 0 eration the gas issuing from the engine ex fxaust pipe enters themuffler through the boss 4, a portion passing directly through the tube8 and nozzle 15 to the mufiier outlet, while the remainder passesthrough the baffle plate 13 into the chamber 12 and thence enters thetortuous passage formed by This passage leads to the chamber 11 which inturn communicates through the annular assage 16 with the muflier outlet.The ow of the gas through the two assages (direct and tortuous) isindicated by arrows in Fig. 1 of the drawing.

The results secured with the structure that has been described will bebest understood by following the action within the muflier during theexhaust of the engine, the interior of the'muffler being at atmosphericpiessure at the start. As the-exhaust gas st enters the ressure withinthe muflier rises momentari y on account of the resist-- ance offeredthe gas by the nozzle and the baffle plates. 'But a jet is at onceestablished at the nozzle, and as the gas forming this jet passes at ahigh velocity through the muffler outlet it has an ejector-like actionthat produces a partial vacuum in the chamber 11'. This reduction ofpressure in the chamber 11 due to the suction of the nozzle iscommunicated to the tortuous passage formed by the baffle plates so thatthe gas that had been retarded is set in more rapid motion through thepassage and this, of course, has the effect of drawing the enteringgasforward into the chamber 12. This suction effect due to the partialvacuum in chamber 1 1 is great enough to more than offset the resistanceoffered the gas by the baffie plates, so that the pressure at once fallsbelow that of the atmos here and there remains to the end of the ex auststroke. Thus, while the ressure rises above that of the atmosphere uringthe first part of the exhaust of the engine, on the other hand, it fallsbelow atmospheric pressure during the latter part of the exhaust, sothat use a multiple nozzle the mean effective back pressure during theexhaust stroke is practically nil.

Considering further the action within the muffler, it is clear that asthe gas is drawn through the tortuous passage it will pass through theperforations of the baffle plates in the form of jets. As these jetsimpinge against the adjacent plates a considerable portion of the energyof the gas is transferred to the plates in the form of heat. Thisprocess is repeated again and again throughout the passage, the gasmeanwhile gradually expanding. As the gas passes through the last baffleplate it ex ands rapidly 1n the chamber 11 and, thus osing most of itsre maining surplus heat, asses out of the muffler into the atmospfferewithout noise.

At the end of the exhaust stroke of theengine thegas left in the mufflerpassages moves forward to fill the partial vacuum in the chamber 11 but,before the pressure in said chamber can be raised to that of theatmosphere by this forward movement of the exhaust gas, atmospheric airis drawn back into the muffler through the casing outlet, the jet 'atthe nozzle having been broken at the closure of the'eng'ine'exhaustvalve, if not' before. The entrance of the com arativel cold outer aircools the muffler p ates an with the added cooling effect of the rapidexpansion in the chambers and passages, the

mufiier is maintained at'a comparatively low temperature; indeed it isfound that the cooling effect extends back some distance in the engineexhaust pipe. I

To review the operation briefly for the sake of clearness, as the gasenters the muffler at the beginning of the exhaust, first a jet Y isestablished and a partial vacuum created in the chamber 11. This partialvacuum is sufficient to more than offset the retarding effect of thebaffle plates so that the pressure in the muffler falls and the gas isdrawn rap idly through the tortuous passage, a portion of its heat beinggiven up to the baffle plates;

and by gradual expansion in the manner described and its remaining sulus heat being lost in the rapid expanslon that takes place as the gasenters the chamber 11. The surplus heat having been removed from the gasit passes quietly from the chamber 11 into the atmosphere. .Finally, thecool outer air is drawn back intothe mufller and assists the coolingeffect of the expansion to maintain the muffler at a low temperature.

becomes too large to Work silently and I then I gas opening into saidchamber, means disposed in said passage for retarding the flow of 120 Inmurders of large capacitya single jet gas therethrough, and means forpartial vacuum in said chamber.

2. In a muffler, the combination of an expansion chamber with means forutilizing a portion of the heat energy of the exhaust gas to create apartial vacuum in said chamber.

3. In. a muffler, the combination of an expansionchamber, a passageopening into said chamber, means for retarding the flow of as throughsaid passage, and means for utilizing a portion of the heat energy ofthe exhaust gas to create a partial vacuum in said expansion chamber.

4. In a muffler, the combination of means for retarding the flow of theexhaust gas with means for accelerating the flow against the resistanceof the said retarding means.

5. In a muffler, the combination of means for retarding the flow of theexhaust gas, with means for utilizing the heat energy of a portion ofthe exhaust gas to accelerate the flow of the remainder of the exhaustgas against the resistance of said retarding means.

6. In a muffler, the combination of a passage for the flow of exhaustgas, means for retarding the flow in said passage, a second passage forthe flow of gas, and means wherey the heat energy of the gas flowingthrough said second passage is utilized to accelerate the flow of gasthrough said first named passage against the resistance of saidretarding means.

7. In a muffler, the combination of an expansion chamber, a passage forthe flow of gas opening into said. chamber, means for retarding the flowof gas through said passage, a second passage forthe flow of gas, andmeans whereby the heat energy of the gas flowing through said secondpassage is utilized to reduce the pressure in said expansion chamber. a

8. In a muffler, the combination of a casing, an inlet and an outlet forthe casing, a circuitous passage leading from the inlet to the outlet,and a direct passage leading from the inlet and opening into thecircuitous passage in a manner such that gas flowing through the directpassage has a suction effeet on gas in the circuitous passage.

9.. In a muffler, the combination of a casing, an inlet and an outletfor the casing, a

creating a passage for the -flow of gas leading from the inlet to theoutlet, means for retarding the flow of gas through said 0nd passage forthe flow of gas leading from said inlet and opening into said firstnamed passage.

10. Ina muffler, the combination of a cas ing, an inlet and an outletfor the casing, an expansion chamber, a circuitous passage leading fromthe casing inlet to said chamber, a discharge passage leading from thechamber to the casing outlet, and a direct passage leading from thecasing inlet and opening into said discharge passage.

passage, and a sec-' chamber, baffle 11. In a muffler, the combinationof a casing, an inlet and an outlet for the casing, an expansionchamber, a passage leading from the casing inlet to said chamber, meansfor retarding the flow of gas through said passage, a discharge passageleading from said chamber to the casing outlet, and a direct passageleading from the casing inlet and opening into said discharge passage.

12. The combination in a muffler of a casing, an inlet for the casing, adischarge passage leading from the casing, an intermediate passageleading from the inlet to the discharge passage, means for retarding theflow of gas through said intermediate passage, an ejector nozzledisposed in said discharge passage, and means for directing a flow ofgas through said nozzle.

13. In a muffler, the combination of a casin an inlet and an outlet forthe casing, an expansion chamber, a passage leading from the casinginlet to said chamber, means for retarding the flow of gas through saidpassage, a discharge passage leading from the chamber to the casingoutlet, an ejector nozzle disposed in the discharge passage, and meansfor directing a flow of gas through said nozzle.

14. In a muffler, the combination of a casing, an inlet for the casing,a discharge passage leading from the casing, an intermediate passageleading from the casing inlet to the discharge passage, means forretarding the flow of gas through said intermediate passage, an ejectornozzle disposed in the discharge passage, and a passage adapted toconduct a portion of the exhaust gas to said nozzle with comparativelyslight retardation.

15. In a muffler, the combination of a casing, an inlet and an outletfor the casing, an expansion chamber, a passage leading from said inletto said chamber, means for retarding the flow of gas through saidpassage, a

discharge passage leading from the expan-- sion chamber to the casingoutlet, an ejector nozzle disposed in said discharge passage, and apassage adapted to conduct a portion of the exhaust gas to said nozzlewith comparatively slight retardation.

16. In a muffler, the combination of a casing, an inlet and an outletfor the casing, a passage leading from the inlet to the outlet, a seriesof baffle plates in said passage, an ejector nozzle disposed at thejunction of said passage and the casing outlet, and a passage leadingdirectly from the casing inlet to said nozzle.

17. In a muffler, the combination of a casing, an inlet and an outletfor the casing, an expansion chamber Within the casing, a passageleading from the casing inlet to said lates in said passage, a dischargepassage eading from the expansion chamber to the casing outlet, anejector nozzle disposed in said discharge passage, and a ass'age leadingdirectly from the casing inet to said nozzle.

l 18. In 'a mufl'ler, the combination of a chamber to receive exhaustgas with means for utilizing the energy of a portion of the exhaust gasto eject gas from said chamber.

- l9. Ina mufiier, the combination of a casing, a plurality of expansionchambers with in said casing'that communicate with each other 1n seriesrelation, and means for utilizing the energy of part of the exhaust gasto rounding the axially disposed passage and forming. acircuitouspassage from the inlet passage to the outlet passage.

21. In a muffler, the comb nation of a cylindrical casing, an inletpassage in one head T of said casing and an outlet passage in ,the

with the outlet rality of conica other head thereof, a straight, axiallydis-,

posed passage leading from the inletpassage and terminating-in a nozzlearranged to dis charge into theloutlet passage, an expansion chamber inthe casing and in communication passage thereof,-and a plubafhe platessurrounding said axially disposed passage and forming acircuitous'passage between the inlet passage and said expansion chamber.I

22. In a ufiier, thecombinationwith a cylindrical casing having an inletport in one end 'andan outlet port in'the otherend thereof, of astraight, open ended tube disposed axially in said casing and secured atits ends to the respective; casin heads, a

nozzle on one endof said tube having its outan expansion chamber in thecasing, a sand eading from the expansion chamber to the outlet ort ofthe casing, a plurality of conical ba e plates arranged symmetrically onsaid tube and extending to the side wall of the casing, each bafileplate being provided with perforations that are staggered with respectto the perforations in the adjacent plates, and means for spacing saidlates whereby a circuitous passage is forme leading from the-casinginlet port to the expansion chamber. r l 23. In a mufiler, thecombination of a casing, means in said casing for absorbing-heat fromthe exhaust gas passing therethrough, and means whereby a current of airis intermittently drawn into said casing in alternating-sequence withthe passage of exhaust gas therethrough.

24. In a mufiler, the combination of an expansion chamber comprising aplurality of compartments that communicate with each other in seriesrelation, an ejector nozzle disposed so as to exhaust the gasfrom one ofthe compartments, and means for directing a portion of the exhaust gasthrough said nozzle.

25. In a muflier, the combination of a casing, an inlet and an outletfor the casing, a plurality of ex ansion chambers communicating with'eacconst tuting a passage leading. from the inlet to the outlet, an ejectornozzle disposed at the junctionof said passage and the easing outlet,and a passage leading from the casing inlet to the nozzle.

In testimony whereof I in presence of two subscribin witnesses; DA IDREID. Witnesses:

S. E. BANKS,

FLORENCE L, SMITH.

' let in line Withthe outlet port of the casing,

char e passage surrounding the said nozzle other in series relation andafi-lx my signature

